JP2003508971A - Communications system - Google Patents

Abstract

(57) [Summary] The present invention relates to a method and apparatus for establishing and canceling a communication connection via a private branch exchange. In this case, the transmission network for transmitting the communication data is preferably implemented as an ATM network or an IP network and is controlled by a separate control network. The advantage of this is that both networks are independent of each other and that simple modular scalability is achieved for broadband communication requirements. The centralized control arrangement allows the use of an existing centralized database of subscribers, and furthermore the connection-related service feature control system.

Description

Detailed Description of the Invention

The present invention relates to a method and a device for establishing and tearing down communication connections, eg for a private branch exchange and terminal equipment connected thereto.

Due to an increase in the communication traffic volume due to an increase in the number of communication subscribers and an increase in the demand for the amount of data to be transmitted, in a switching device such as a private branch exchange, the amount of data to be transmitted per communication connection and There is an increasing demand on the number of connectable communication terminals. Current equipment is for example TDM
It is based on the (Time Division Multiplexing) method, in which case communication data of various connections are transmitted in specified time slots each time. The connections of the various communication partners are formed by a switch matrix, which according to the control information assigns the incoming time slots in the incoming connection to the outgoing time slots of the outgoing connection. Switching matrices of this kind are usually fixedly selected and can only form a defined number of connections, which often makes it difficult to match the exchanges on demand. Another problem with this type of device is the limited data capacity of the timeslots.
For example, one switching matrix can establish 4096 connections, while a maximum of 64 kbits of data can be transmitted in one time slot. Therefore, the increase in the number of subscribers can be considered only in the unit of 4096 subscribers. However, in order to use these different expansion stages, extra development costs are required to match the switching equipment with the increase in the number of subscribers. A flexible increase in the amount of communication traffic per connection is not possible as it is, and can be executed at most by establishing two or more communication connections, that is, in the unit of 64 kbit. That said, this kind of wideband multiplication is actually IS
It is not implemented for transmission via DN (Integrated Services Digital Network), and the terminal device cannot be used for that purpose.

The object of the present invention is therefore to provide a method and a device for preparing a communication connection with a high degree of flexibility in matching the number of communication connections to be provided, the amount of communication traffic per connection and their spatial extent. It is to be configured to be guaranteed. This task is claimed as a method.
It is solved by the structure described in the characterizing part of the above, and the device is solved by the structure described in the characterizing part of claim 9. The dependent claims show embodiments of the invention.

Particularly preferably, the control function and the connection function are performed by functional units which are spatially separated from one another. The reason is that in such a way, it is possible to construct a decentralized switching system having the advantageous characteristics of the central system without incurring a large development cost.

For this purpose, the control function is preferably implemented in the control network according to the method described above, and the connection function is provided via the transmission network, preferably by using a connection device. This connection device can be placed on any form of transport network suitable and available depending on the type of user. In this way, it is possible to take into account the increase in communication traffic by means of an appropriately selected transmission network with sufficient transmission capacity, while the control, for example the control of the control network, does not need to be expanded, and it remains as is. Can be maintained at. Moreover, the method according to the invention makes it possible to operate spatially distantly distributed communication devices, in which case it is particularly advantageous if only the control information is transferred to the central control unit. The connection is provided via a separate transport network with the appropriate topology.

When using a central control unit according to one embodiment of the method described above, it is advantageous to use existing databases and control schemes in the central switching unit for the purpose of controlling the distributed switching unit of the transmission network in providing the communication connection. Can be used as is. In this way, a smooth transition from existing solutions to the new solutions mentioned above is guaranteed, while the advantages of central data management and fault detection and fault removal remain unchanged with increased flexibility.

Particularly advantageously, a connection for distributed devices is established in the transmission network. In this way, it is advantageously possible to provide transmission connections within the distributed device and their data streams do not overload the central control unit. In this case, a high degree of redundancy is realized and the transmission network can in each case use state-of-the-art switching equipment, which is currently present, for example, in ATM switching equipment, Ethernet switching equipment or IP switching equipment. And so on.

Particularly advantageously, according to one embodiment of the method described, the central unit controls the distributed switching unit. In this way, it is possible in this way to connect a plurality of distributed devices to one another, which together act as if they were the only switching device. This allows a centrally implemented connection-related service feature to be realized for a communication connection via the transmission network, which can therefore be realized without additional costs on the transmission network side. Nor is it necessary for the control side to adapt the provided service features in order to make them available throughout the network. Advantageously, a method of this kind can be used throughout the network in a distributed switching system, which is otherwise only available in a single local switching system and not in multiple switching systems. Is. Even more preferably, applications and interfaces for applications that were previously only accessible to a single system can also be utilized for distributed switching equipment.

Particularly preferably, in a variant of the method described above, the terminal devices accessible by a time slot multiple connection are connected via a transmission network, in which case a communication connection is provided via the transmission network. For the purpose of controlling, the control device generates new appropriate connection information from the connection information related to the conventional time slot. In this way existing methods for controlling the TDM switching matrix can be used for the purpose of establishing a connection according to this variant of the method according to the invention.

However, the method according to the invention is also suitable for other dynamically constructed connections, such as ATM or IP connections, without any restrictions. To the control unit, these connections look like conventional TDM connections and are treated as such, for which reason also conventional connection information relating to timeslots is generated, which are new to the transmission network. Converted back to connection information. In this way, terminal equipment not associated with time slots (not TDM-based) can also be connected, for example IP terminal equipment or ATM terminal equipment, ie IP telephones, computers and ATM terminals.

In this way, the existing control method of the TDM connection can be used for the purpose of establishing another connection.

Advantageously, this reduces the technical implementation costs for this variant embodiment and facilitates the transition from the existing method to the new method. This is because it is only necessary to match this control information to the requirements of the transmission network.

Particularly advantageously, in one embodiment of the method described, the transport network connection is implemented in asynchronous transfer mode. This is because ATM networks are technically mature and provide the basis for greater transmission capacity and their flexible distribution. Moreover, ATM networks are particularly suitable for time-critical transmission at high data rates via distributed switching equipment. This is because it can guarantee the quality features required for audio and video (quality of service).

Particularly advantageously in one embodiment of the method described above, the service feature is provided via a central control unit. This is because in that way any arbitrary transport network can be routed to the existing service feature control network. Also, in this way, existing methods can advantageously be used to provide the service features, without each transport network having to uniquely match the service features. In this case, the transmission network can be exchanged without increasing the effect on the control device.

Particularly preferably, the device for providing a communication connection comprises, for example, a separate control network and a separate transmission network for transmitting signaling information, the transmission network being suitable means. Controlled by the control network via. The separation of control and transmission networks relates to the route of information through the network, or the logical topology of the network. Physically, different networks or the same network can be utilized for transmission. In this way, a minimal configuration is provided in order to solve the problem of providing a communication device that is flexible and expandable for data transmission rates of arbitrary magnitude. This can advantageously be subscriber-specific matched.

[0016] Preferably, the transmission network has a decentralized device for connecting communication terminal equipment and a decentralized switching device provided in the area thereof, which provides a communication mechanism in the transmission network. . In this way, it is possible to provide a communication connection via a single private branch exchange for an area over a fairly large area, while minimizing the cabling costs. This is because it is only necessary to guide the control network to the center, and even if it is a network that has already been installed or a public network for connecting distributed switching devices via the transmission network. You can choose the most suitable topology.

Advantageously, according to one embodiment of the described device, a central control device is provided in the control network. The reason is that this allows centralized subscriber management and connection control and associated data retention and maintenance and security, problem identification and elimination, and provision of new software distributions. Because.

[0018] Preferably, in one embodiment of the previously described device, the central control device is connected to a device providing service features, the service feature providing device being a component integrated in the control device. be able to. This is because doing so allows centralized provisioning of connection-related and other service features with minimal installation and implementation costs. In addition to the service feature, those devices that provide the service feature may utilize additional applications and interfaces for applications beyond the scope of the communication service feature. Advantageously in this way an external server such as a call center solution, CTI (Computer Telephony Integrati)
The server for on) can be centrally coupled via a standardized interface.

Particularly preferably according to one embodiment of the device described, the private branch exchange can combine at least two distributed switching devices with one central control unit. This makes it possible to provide a distributed private branch exchange with a minimum of configuration, which can be optionally expanded in a modular manner.

Particularly preferably according to one embodiment of the above-mentioned minimum configuration, a device is provided for providing connection-related and other service features. This is because by doing so it is not necessary for the private branch exchange to provide or implement a distributed form of service features in the transmission network.

More particularly preferably, an emergency control device is provided in the area of at least one distributed device, which enables an emergency operation between the communication terminals connected to this distributed device. This is done when the central control unit fails or the control network is shut down. In this way, a single system provides a very high availability, which corresponds to the availability when multiple systems are integrated in the network.

[0022]   Next, embodiments of the present invention will be described with reference to the drawings.

[0023]   Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a conventional communication device. FIG. 2 is a diagram showing an example of a new communication device. FIG. 3 is a diagram showing a message flow in a known switching system. FIG. 4 is a diagram showing a message flow using connection information related to a time slot for a transmission network.

FIG. 1 shows an example of a known private branch exchange 150 with two peripherals P1 and P2, which peripherals are respectively telecommunications terminals KE1 and KE2 operating digitally or in analog form. Are connected. In this case, the peripheral devices P1 and P2 are provided in the same space area as the central device ZE1.
Illustratively, they are located in the same room as the central unit or in the same cabinet. Each terminal device fills a prescribed time slot in a PCM (Pulse Code Modulation) data stream with communication data. The digital or analog communication terminal equipment KE1, KE2 is respectively connected to subscriber line modules SLM01 and SLM02, which modules provide digital data which is assigned to or originates from individual terminals. Feeds the PCM data stream through time slots specified per signaling or PCM
Retrieve from data stream. In FIG. 1, these PCM data streams are designated by reference numeral 100.
Or 200 is attached. Furthermore, the signaling connection with the reference number 110 or 210 is also drawn. It should be noted here that this is merely a logical representation, not a physical representation. actually,
The transmission data and the signaling data are transmitted on the same connection cable.

Further, here, the peripheral devices P1 and P2 are also line trunk units LTC1 and L2.
The TUC2s are also depicted, which control the data traffic to the subscriber line modules of the individual devices distributed. The peripheral device P1 is supplied with the signaling data via the line 110, and the peripheral device P2 is supplied with the signaling data via the signaling line 210.

In the case of this device, as shown here, both the information to be transmitted and the signaling information are provided to the central device ZE1. In this case, the message device DCL collects and distributes the messages 2, which are exchanged between the central device ZE1 and the peripheral devices P1, P2. Further, the call processing device CP controls the establishment and cancellation of the connection, and for this purpose, the call processing device utilizes the device-specific interface function DH realized in the form of a program module, for example. At that time, a setting command for the switching matrix MTS is issued. These setting instructions basically indicate which input of the switching matrix should be connected to which output in order to provide a communication connection. That is, the control and connection functions are performed by a single spatially integrated functional unit in the communication network.

A problem arises with such a configuration, because all the data to be transmitted must be directed to the central unit ZE1. This applies, for example, even when two communication terminal devices connected to the same peripheral device P1 try to communicate with each other. The cabling required in this type of equipment becomes more complex as the distance from the terminal equipment to the central equipment ZE1 becomes more and more, and this kind of equipment restricts the planar spread of the exchange facility.
Or, when covering a relatively large area, the installation is very expensive.

An alternative to flattening out a single device 150 is a plurality of devices 15.
Incorporating 0 into the network would lose the benefits of a single device. Moreover, a further difficulty in incorporating this type of device 150 in a network is that additional trunk components must be installed and installed with additional connection cables each time.

Even in the case of being modularly expandable, in this type of device, problems occur in terms of the number of connections and the amount of data to be transmitted. Only one switching matrix MTS can be provided as a whole. Thus, in the extreme case, a new switching matrix with, for example, 4096 terminals must be purchased and installed for one additional connection. In this type of system, the transmission rate is limited by, for example: That is, ISDM
As set in the standard, data can be transmitted only at a maximum of 64 Kbit per time slot or other data amount set by the management side or technically limited. With this type of configuration, different data rates cannot be used for individual communication connections.

FIG. 2 depicts one embodiment of a new device configuration for establishing a communication connection. This device illustratively has the structure of a private branch exchange 250.

The same components as in the device of FIG. 1 are provided with the same reference numbers. As can be seen in FIG. 2, a separate transmission network 700 and a separate control network 310/410 are provided. The advantage of such a structure in a switching device is that it allows the use of networks already provided for transmission networks, such as public or private networks. Here, only the control network has to be routed to the central unit ZE2.

The digital or analog communication terminals KE1 and KE2 are depicted as they are connected to the subscriber line modules SLM01 and SLM02, respectively. However, the present invention is not limited to this, and in this type of device 250, a terminal device that can be connected to the transmission network 700 directly or bypassed or without passing through the SLM0 is also conceivable, and It is also possible to integrate such terminal devices. In other words, ATM terminal equipment and IP (Internet P
rotocol) -based terminal equipment can also be connected.

Furthermore, as shown in this figure, the distributed devices DZ1, DZ2 respectively have distributed switching devices CS1, CS2, which can be configured, for example, as ATM access devices. Furthermore, it is drawn in this figure that the switching matrix MTS0 is no longer used for the task of the connection.

Therefore, in this device, the control information for establishing the communication connection is supplied only to the individual distributed switching devices CS1 and CS2 via the control lines 410 and 310, which is the control information related to the time slot. Derived from. Further, as can be seen from this figure, in the data path 300 or 400, conversion of PCM data into cell data according to the standard of the transmission network 700, for example, ATM cell data is executed. It should be noted here that the use of ATM networks as the transport network is only used as an example. Ethernet and other IP or TDM connections are also considered for this. This choice depends on the intended use and covers a wide range of networks available in both the narrowband and wideband fields.

Since in FIG. 2 there is no communication connection to the central unit ZE2, in this embodiment DZ1 and DZ2 to the central unit ZE2, for example a tie line (tie).
There is no need to pay the telephone charges that may be incurred in order to connect via a public line such as line). This is because DZ1 to DZ2 when the peripheral device 150 according to FIG. Had occurred in the communication to.
Advantageously, call processing depending on the transport network is carried out in the decentralized exchanges CS1, CS2, which is essentially limited to the basic call functionality. In this case, the service feature is realized and provided by the central control unit ZE2. The connections between the various distributed devices are controlled by the central device ZE2 via signaling. The advantage of this device is that it can operate in both narrow and wide band. Further, the transmission network may be constructed on a public network, a dedicated network, or a mixed network of both. It is also possible to assign a remote distributed device to the central device ZE2 without being spatially restricted,
In doing so, very large mechanisms can also be provided by such private branch exchanges, while such private branch exchanges are used to provide communication connections to large areas. Retaining the central unit for control allows existing software to continue to be used with minimal changes. If control is distributed like a switching matrix, new methods for control must be developed, and a mechanism must be provided to guarantee the consistency of the distributed database. Yet another advantage of this type of device 250 over the system networked by the device 150 is that the distributed system is a single system, and therefore can only run service features implemented in the system. It is possible. Therefore, it is not necessary to adapt the individual service features in order to be able to operate them in the network.

As an example, FIG. 3 schematically shows the message flow of a conventional communication system for establishing a connection between two peripheral devices, these two peripheral devices being the terminal equipment of the subscriber A. The TLNA and the terminal device TLNB of the subscriber B are connected. The temporal flow of a message or control message is expressed in the direction from top to bottom. First, the subscriber A goes off-hook, and signaling information OFF HOOK is generated. Then, the desired communication partner is selected by inputting the dialing information, and this dialing information is transmitted from the device-specific interface module DH to the call processing device CP of the subscriber A.

The message SEIZURE is transferred by the dialing evaluator WABE for dialing information to the call processor CP of the subscriber B. The device-specific interface module DH playing a role there, the explicit time slot of the PCM data path defined for that connection, eg PD1, eg Z
S1 is allocated and a control message TSL_ASSSIGN to the subscriber line module SLM01 is generated. This control message informs the subscriber line module SLM01 of the explicit time slot ZS1 to be used for the connection and the determined PCM data path PD1.
The explicit time slot ZS1 in the PCM data path PD1 applies for the connection element between the subscriber line module SLM01 and MTS. The second explicit time slot ZS2 in the explicitly defined second PCM data path PD2 applies for the connection component between the MTS and the subscriber line module SLM02. Also in the control message TSL_ASSSIGN, the information ZS2 and PD2 are posted to the subscriber line module SLM02. TDM-based private branch exchanges typically utilize the TDM switching matrix MTS to physically connect individual subscribers. A set command PATH_CONNECT1 is issued for this switching matrix, which causes the time slot ZS1 of the PCM data path PD1 to be PCM.
It is coupled to the time slot ZS2 of the data path PD2. As a result, the connection elements are combined to form a connected section between SLM01 and SLM02.

In the context of the implementation of the method according to the invention, it is not important whether the CP and DH are components of the control software, whether they exist as separate modules or are integrated. Absent.

FIG. 4 schematically shows a message flow between two distributed devices as an example. These distributed devices have terminal equipment TLNA of subscriber A and terminal equipment T of subscriber B.
LNB is connected. The ATM network is used here as a transmission network as an example. The temporal flow of a message or signaling message is represented from the top to the bottom. The functional unit STMA converts the time slots of the PCM data stream into a cell stream of ATM cells. Figure 2
In this case, devices of this kind are respectively integrated in the distributed switching device CS1 or CS2 and are therefore not represented separately.

The difference between this flow and the flow shown in FIG. 3 is only when the set command PATH_CONNECT1 is issued for the TDM switching matrix. Here, instead of the set command PATH_CONNECT1, a control message PATH_CONNECT2 is generated, which is sent to the distributed switching device. In response, the distributed switching equipment establishes a connection in the transmission network. When the ATM transmission network is used, ATMSVC (ATM Switched Virtual Connection) is established by the ATM signaling method, for example.

For this purpose, the control message PATH_CONNECT2 must include the time slot information ZS and the data path information PD, which can be directly extracted from the set command PATH_CONNECT1, for example. Furthermore, the central control unit only needs to specify the address depending on the transmission network of the distributed switching unit with which the connection is to be established. In other words, the data that must be provided to the central control unit as information about the transmission network is limited to the transmission network-dependent address of each distributed switching device. The central control unit also obtains the required address from the time slot information ZS and the data path information PD. An allocation table in the central database DB controls the mapping of time slots / data paths to distributed switching equipment.

Further information can be included in the control message PATH_CONNECT2, and the control message PATH_CONNECT can be generated in a plurality of unique forms. When trying to establish a connection with different bandwidths, information about the desired bandwidth can also be included in the control message PATH_CONN2. As an alternative to this, it is also possible to exchange bandwidth information directly between each subscriber line module and the switching device.

When the distributed switching device establishes a connection in the transmission network 700 after receiving the PATH_CONN2 message, user data is transmitted through the network. The correspondence between the user data stream in the data path 300/400 between the subscriber line module and the distributed device DZ and the connection between DZ1 and DZ2 is made by mapping the time slot slot information ZS and PD to the connection identifier of the connection. It is done by doing. That is, although the sequence for establishing a connection from the central controller ZE2 via the transmission network may be complicated, in order to establish the connection via the transmission network, the call processing device of the transmission network must be used. All that is required is to transmit those addresses to. The transport network specific call processor handles the rest.

That is, according to this message flow, the PATH_CONNECT command is replaced by the call processing device specific to the transmission network. In order to be able to connect TDM-based subscribers by means of distributed switching devices independent of the transport network, it is necessary to convert the time slots into transport units. This is done, for example, in a conversion unit, such as an STMA, which is provided for each distributed device and is preferably inserted in the path of the user data. For this purpose, ATM-PCM gateway or IP-
A PCM gateway can be provided.

Communication between the TDM-based subscriber line module and the conversion unit takes place, for example, via connections on the rear side of the printed circuit boards of the individual distribution devices. for that reason,
A bus is provided on the printed wiring board to connect all components to each other. The set instruction for inserting into the conversion unit is preferably generated autonomously by the distributed switching device from the PATH_CONN2 message.

However, the method according to the invention is not limited to dynamically established dialing connections and can also be used for ATM PVC (AT
MPVC Permanent virtual connection). In this case, the information about the address needs to be exchanged with the information controlling the use of the fixed connection.
In addition, other forms of data transmission can be used, such as IP connections.

[Brief description of drawings]

[Figure 1]   It is a figure which shows the conventional communication apparatus.

[Fig. 2]   It is a figure which shows the example of a new communication apparatus.

[Figure 3]   It is a figure which shows the flow of the message in a well-known exchange system.

FIG. 4 is a diagram showing a message flow using connection information related to a time slot for a transmission network.

─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Helmut Luckle             Federal Republic of Germany Taufkirchen             Urregi Strasse 12 (72) Inventor Liner Vindecker             Federal Republic of Germany Munich Gustav             -Heinemann-Ring 94 (72) Inventor Harold Linke             Federal Republic of Germany             Holbein-Strasse 8 (72) Inventor Axel Bürk             Federal Republic of Germany Taufkirchen             Ruhrweg 17 (72) Inventor Steffie Winkler             Gauting Lulu, Federal Republic of Germany             Beck-Wake 13 (72) Inventor Antonius Emerink             Federal Republic of Germany Munich Ain             Gerstraße 4 (72) Inventor Egon Klein             Germany Germering Mün             Hinner Strasse 14 (72) Inventor Joseph Varler             Federal Republic of Germany Taufkirchen             Ruffstrasse 33 / Car F-term (reference) 5K030 HB11 JA13 LB02 LB03                 5K051 AA09 BB01 BB02 DD01 DD13                       FF00

Claims (16)

[Claims] 1. A method for establishing and / or canceling a communication connection, comprising: a) a connection function (CS1, CS2, 700) for establishing and / or canceling a communication connection for transmitting communication data, at least in a communication network. One first functional unit, b) a control function for controlling said connection function, performed by a second functional unit (ZE2, 310, 410) of the communication network, and c) these first and Method for establishing and / or breaking a communication connection, characterized in that the second functional units are spatially separated from each other. 2. A) performing signaling to control the establishment and / or teardown of a communication connection, b) establishing and / or tearing down a connection via a transport network (700), and c) a control network (310). , 410). 3. The method according to claim 2, wherein signaling is controlled by a central unit (ZE2). 4. The method according to claim 1, wherein a communication connection is established in the transmission network via at least one distributed device (CS1, CS2). 5. The method according to claim 3, wherein the central unit (ZE2) controls the distributed switching units (CS1, CS2). 6. A communication connection (300, 4) to a communication terminal device (KE1).
00) to establish and / or cancel the connection, establish a connection via the transmission network (700), generate at least one time slot control information in the central unit (ZE2), and transmit the time slot control information to the transmission network (700). )
The method according to any one of claims 1 to 5, which is used for establishing a connection in. 7. Method according to claim 6, characterized in that the time slot control information is combined with information specific to the transmission network and transmitted to the distributed device (CS1, CS2). 8. The method according to claim 1, wherein the transmission is carried out according to an asynchronous transmission method via a communication connection (700). 9. The method according to claim 2, wherein at least one connection-related and / or central device-related service feature or application is provided by the central device (ZE). 10. An apparatus for establishing and / or canceling a communication connection, comprising: a) a transmission network (70) providing a communication connection (300, 400).
0) and b) a control network (310, 410) for controlling the establishment and / or cancellation of the communication connection (700, 300, 400), and c) the establishment and / or connection of the transmission network (300, 400, 700). Alternatively, means for controlling the cancellation by the control network (310, 410) is provided, and the means is arranged spatially separated from the transmission network, and establishes and / or establishes a communication connection. A device to eliminate. 11. At least one distributed device (SLM01, SLM02) is provided for connecting communication terminal equipment (KE1, KE2) and provides a communication connection in a transmission network in the area of the distributed device. Exchange device (
Device according to claim 9, wherein CS1, CS2) are provided. 12. The device according to claim 9, wherein the control network (310, 410) comprises a central unit (ZE2) for control. 13. Central means for providing at least one connection-related and / or central device service feature or application, said central means being connected to a central device (ZE2). 11. The device according to item 11. 14. A communication terminal device (KE), which is configured as an exchange switching device.
1, KE2) to connect at least two distributed devices (DZ1, DZ2)
The device according to claim 10 or 11, wherein the device is provided. 15. The device according to claim 12 and 13. 16. A control device (CS1) in the area of a distributed device (DZ1, DZ2).
, CS2) are provided, said controller providing a communication connection in the area of said distributed device when a central controller (ZE2) is unavailable. apparatus.